In overweight and obese women, fetal ultrasound biometry accurately predicts newborn measures

Introduction: The aim of this study was to evaluate the association between fetal ultrasound and newborn biometry and adiposity measures in the setting of maternal obesity. Material and Methods: The study population involved 845 overweight or obese pregnant women, who participated in the Standard Care Group of the LIMIT randomised trial (ACTRN12607000161426, 9/03/2007). At 36 weeks gestation, fetal biometry, estimated fetal weight (EFW) and adiposity measures including mid-thigh fat mass (MTFM), subscapular fat mass (SSFM), and abdominal fat mass (AFM) were undertaken using ultrasound. Neonatal anthropometric measurements obtained after birth included birthweight, head circumference (HC), abdominal circumference (AC) and skinfold thickness measurements (SFTM) of the subscapular region and abdomen. Results: At 36 weeks gestation, every 1 g increase in EFW was associated with a 0.94 g increase in birthweight (95% CI 0.88–0.99; P < 0.001). For every 1 mm increase in the fetal ultrasound measure, there was a 0.69 mm increase in birth HC (95% CI 0.63–0.75, P < 0.001) and 0.69 mm increase in birth AC (95% CI 0.60–0.79, P < 0.001). Subscapular fat mass in the fetus and the newborn (0.29 mm, 95% CI 0.20–0.39, P < 0.001) were moderately associated, but AFM measurements were not (0.06 mm, −0.03 to 0.15, P = 0.203). There is no evidence that these relationships differed by maternal body mass index. Conclusion: In women who are overweight or obese, fetal ultrasound accurately predicts neonatal HC and AC along with birthweight.